Arrangement in tree-processing assembly

ABSTRACT

The present invention relates to an arrangement in a tree-processing assembly of the type comprising a frame base (2) which is connectible to the tip of a crane via a rotator (3) and with which a pivotable carrier (5) is hingedly connected, said carrier comprising at least one set of grapples (6, 6&#39;, 6&#34;) for gripping and holding a log, and a cutting tool, such as a chain-saw guide bar (12), attached to the lower part (11) of the carrier. On the lower part (11) of the carrier (5) there is mounted a rotary saw blade (15) which is pivotably movable between an inactive position in which it is swung in towards the carrier, and an active position in which it is swung out from the carrier and in which it can cut, by means of an outer half, a shrub layer and/or small trees.

FIELD OF THE INVENTION

The present invention relates to an arrangement in a tree-processingassembly of the type comprising a frame which is connectible to the tipof a crane via a rotator and with which a pivotable carrier is hingedlyconnected, said carrier comprising at least one set of grapples forgripping and holding a log, and a cutting tool, such as a chain-sawguide bar, attached to a lower part of said carrier.

Such tree-processing assemblies can be divided into two different basictypes, e.g. so-called "harvesters" and "pure felling" assemblies. Aone-grip type harvester comprises, in addition to grapples and a cuttingtool, a number of limbing knives and at least one set of feed rolls bymeans of which the felled tree held by the grapples, can belongitudinally fed relative to the carrier and thus be separated fromthe limbs. By means of such harvesters, a tree can thus be felled,delimbed and cut to suitable lengths. However, in conventional fellingassemblies, there are, no feed rolls, and therefore such assemblies canonly cut the tree at the root, without delimbing it.

BACKGROUND OF THE INVENTION

In modern forestry, tree stands are in most cases thinned by means ofe.g. "one-grip" harvesters. A frequent problem in such thinning iscaused by the thicket or shrub layer which is often found adjacent thetrees which are to be thinned and cut. Such thicket normally growsaround the lower part of the tree to be cut, thus preventing a clearview by the person who operates the harvester from a driving-cab locateda considerable distance from the tree. Besides blocking the operator'sview, the thicket also causes problems by easily finding its way betweenthe the trunk and the saw chain mounted on the guide bar of theharvester, which serves as a cutting tool. As a result, the chain mayslip or jam and, consequently, lose its capacity of effectively cuttingthe trunk. To eliminate the problems caused by thicket surrounding thetree, in practice there is usually a special operator who manuallycleans the tree stand from the shrub layer by means of a conventionalbush saw, before the actual thinning is carried out. However, this workis costly and involves a number of drawbacks. One drawback is that thecleaning operator does not know in advance which direction the harvesterwill be moving towards the tree to be thinned. Thus the operator mustremove all the thicket in a 360° sector around the tree. Removingsubstantially all the thicket in this manner while leaving completelybare surfaces around the tree is contrary to recent environmentalprotection practices which recommend a certain amount of shrub layer ina growing forest, to create a favourable environment for forest animals.Such clear-cleaning involves extensive work which takes much time andthus is expensive. In practice, the cost for manual thicket-cleaningalone is estimated at 15-20% of the total thinning cost. A furtherproblem relates to the technical planning, particularly for large forestowners with a large number of scattered stands. Thus, it is extremelydifficult to plan the cleaning operator's work to coordinate efficientlywith the thinning operation.

BRIEF DESCRIPTION OF THE INVENTION

The present invention aims at overcoming the above-mentioned drawbacksby eliminating the need for manual cleaning and for permitting theremoval, as required, of thicket and shrub layer which may beobstructing the thinning operation. According to the invention, this isachieved by providing on the lower part of the carrier of atree-processing assembly of the above-mentioned type, there is mounted arotary saw blade which is pivotably movable between an inactive positionand an active position in which it can cut shrub layers and/or smalltrees.

According to a preferred embodiment of the invention, the saw blade isdismountably arranged on a shaft which is rotatably mounted andconnected to a hydraulic motor, which in turn, is arranged on a supportmember. The support member may be a plate, which in turn is articulatedto the lower part of the carrier. In turn, a hydraulic cylinder extendsbetween the support member and the carrier, the support member and,thus, the saw blade being pivotable by means of the hydraulic cylinderbetween a substantially vertical, swung-in position and a substantiallyhorizontal, swung-out position.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the drawings

FIG. 1 is a schematic, simplified front view of a "one-grip" typeharvester with a cleaning arrangement according to the invention,

FIG. 2 is a perspective view of a cleaning arrangement according to theinvention, and

FIGS. 3 and 4 are enlarged side views of the cleaning arrangementaccording to FIG. 2, in two different positions.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

In FIG. 1, a "one-grip" type harvester is generally designated 1. Theharvester comprised, in a conventional manner, a frame 2 which, via arotator 3, is connected to a mounting 4 which in turn can be attached tothe tip of a crane mounted on an off-road vehicle. The frame 2 is via ahinge (not shown) connected to a carrier which in its entirety isdesignated 5 and which in FIG. 1 is shown to be positioned in asubstantially vertical position. By means of a hydraulic cylinder (notshown) acting between the frame 2 and the carrier 5, the carrier can bepivoted from the vertical position shown in the drawings, to asubstantially horizontal position in which the carrier is swungforwards, when viewed from the plane of the drawing. The carrier 5supports a number of grapples 6, 6', 6" which are each pivotable bymeans of a respective hydraulic cylinder 7 with each having a limbingknives 8. Knives 8 have obliquely ground surfaces forming cutting edgesby means of which a passing log can be delimbed. The carrier 5 supportstwo feed rolls 9, 9' which are pivotable towards and away from eachother. The feed rolls, which are rotatable by means of built-inhydraulic motors 10, 10', serve to press against a cut log received bythe grapples, and to move the log axially relative to the carrier fordelimbing thereof. In a lower box-shaped member 11 of the carrier 5, acutting tool in the form of a chain-saw guide bar 12 is provided. Thechain can be moved by means of a hydraulic motor 13, the guide baritself being pivotable between an inactive position in the box-shapedmember 11 and an active position swung out from the box.

The arrangement described above is essentially conventional in allmaterial aspects.

According to the invention, a cleaning assembly designated in itsentirety by 14 is connected to the lower member 11 of the harvester 1and in particular, to the carrier 5. The characteristic features of thiscleaning arrangement are shown in greater detail in FIGS. 2-4, to whichreference is now made.

The active operating component in the assembly 14 is a rotatable,toothed saw blade 15 preferably of a conventional type. It isdismountably arranged on a shaft which can be the output shaft of ahydraulic motor 17, the latter being mounted on a supporting plate 18.This is, in turn, articulated in association with the lower part of thecarrier via hinges 19 arranged at the outer end of brackets 20 extendingfrom the lower member 11. To the upper side of the supporting plate 18there is attached a mounting 21 for a hinge 22 of a hydraulic cylinder23, whose opposite end is articulated to the carrier 5 via a hinge 24.In the embodiment shown, the piston rod of the hydraulic cylinder isconnected to the hinge 22, while the cylinder itself is connected to thehinge 24 associated with the carrier 5. The dismountable arrangement ofthe saw blade 15 on the shaft 16 can advantageously be achieved by usingtwo supporting discs 25 with internally threaded holes, and by usingscrewed to an externally threaded portion of the shaft 16. A worn-outsaw blade may thus be easily and quickly removed from the shaft, byunscrewing the outer supporting disc, and replacably by a new saw blade.

The supporting plate 18 connected with a base plate 27 by an innercross-member 26. The base plate 27 is spaced from the supporting plateand the inner half of the saw blade is accommodated in the space formedbetween the plates 18 and 27. As a result, the saw blade is wellprotected while in its inactive, swung-in position shown in FIG. 3. Inthe area below the saw blade there is further arranged a yoke 28 whichprojects from the lower edge of the lower member 11 of the carrier. Asis evident from FIG. 3, the yoke 28 projects a distance beyond the baseplate 27 of the saw blade holder so that the saw blade and its holder,in the inactive position illustrated, are reliably protected againstmechanical damage caused by hard objects, such as stones, stumps andthick trees. Also, in the active position illustrated in FIG. 4, theyoke 28 protects the saw blade holder from mechanical damage as theouter end of the yoke is in positioned approximately the same verticalplane as the outer parts of the saw blade holder, only a portion of thesaw blade projects beyond this plane.

Although the yoke 28 is shown as being inclined in the drawings, it mayalso be entirely straight, extending from the bottom side of the lowermember 11. Such a straight design would also allow the same blade to beslightly lowered by arranging the brackets 20 lower down on the outsideof the lower member 11.

As shown in FIG. 2, the hydraulic cylinder 23 is a double-actingcylinder and is fitted with suitable hydraulic lines 29, 29'. Thehydraulic motor 17 is supplied with hydraulic fluid via lines 30, 30'.It is per se conceivable to control the hydraulic motor 17 and thehydraulic cylinder 23 separately by rotating the saw blade independentlyof whether the hydraulic cylinder is activated or not. In practice, itis preferred to synchronize the operation of the hydraulic motor withthe operation of the hydraulic cylinder in such a manner that thestarting of the saw blade 15 is automatically accompanied by activationof the positive chamber of the hydraulic cylinder, i.e. the saw blade,once it has been caused to rotate, is swung out. Inversely, once the sawblade stops rotating, the saw blade can be swung back to its inactiveposition. Such synchronisation can be carried out by suitablyintegrating the above-mentioned lines into the existing system ofhydraulic lines that is required for the other components of theharvester.

The above-described arrangement operates in the manner described below.When the harvester 1 is moved against the tree selected to be cut, whichtree is surrounded by a shrub layer blocking the operator's view, thesaw blade 15 is swung out to the active position shown in FIG. 1. Inthis position, the saw blade can be quickly moved forwards to individualshrubs and small trees by moving the tip of the crane and rotating theentire harvester via the rotator 3, the shrubs and small trees being cutas soon as the rotating saw blade comes into contact with them. It is,of course, sufficient to remove only the vegetation in a limited sector(e.g. 90°-120°) in the area in front of the tree to be thinned and leavethe remaining vegetation surrounding the tree. Such cleaning can inpractice be carried out very quickly, for example in 10-20 s. After thethinning operation has been completed, the saw blade is stopped andswung into the position shown in FIG. 3, whereupon the harvester, whichis unobstructed, can smoothly and effectively grasp the tree and processit in the usual manner, i.e. fell, delimb and cut it to suitablelengths.

The advantages of the invention are obvious. According to the presentinvention, the need for costly manual cleaning is eliminated, and thus,that the planning of the thinning operation is facilitated to aconsiderable extent. Moreover, there is no need for completely cleaningthe area surrounding a tree because the direction that the harvesterwill be moving towards the tree is already determined when the cleaningassembly according to the invention, is activated. The result is thatonly a limited sector in front of the tree requires cleaning.

POSSIBLE MODIFICATIONS OF THE INVENTION

The invention is not restricted only to the embodiment described aboveand shown in the drawings. The saw blade included in the arrangement canalso be mounted on other types of holders other than the one illustratedin the drawings. Furthermore, the saw blade can be swung between its twopositions in ways other than by means of a hydraulic cylinder, although,in practice, a hydraulic cylinder is preferred. Additionally, thecleaning saw blade can be mounted on an arm which is pivotable relativeto the carrier in a horizontal plane, instead of in a vertical plane,and more particularly between an active front position and an inactiverear position, instead of a swung-out and a swung-in position asillustrated in the drawings. It is also possible to apply the inventionto other types of tree-processing assemblies, other than a "one-grip"type harvester, such as "pure felling" assemblies and "two-grip" typeharvesters.

I claim:
 1. In a tree-processing assembly comprising a frame (2), arotator (3), and wherein said frame is connectable to a tip of a craneby said rotator, a pivoted carrier (5) hingedly connected to said frame,said carrier having at least one set of grapple means (6,6'6") forgripping and holding a log, and a cutting tool (12) attached to a lowerpart (11) of said carrier, the improvement wherein a rotary saw blade(15) is mounted on said lower part (11) of said carrier (5), said rotarysaw blade (15) being pivotally mounted for movement between an inactiveposition and an active position in which said rotary saw blade (15) cancut material.
 2. An assembly as claimed in claim 1, wherein said rotarysaw blade (15) is dismountably mounted on a shaft (16), said shaft (16)being rotatably mounted, a hydraulic motor (17) connected to said shaft(16), said hydraulic motor mounted on a support member (18), saidsupport member (18) being pivotally mounted on said lower part (11) ofsaid carrier (5), and an hydraulic cylinder (23) extending between saidsupport member (18) and said carrier (5), said support member (18) andsaid saw blade (15) being pivotal between a substantially vertical,inactive, position and a substantially horizontal, active, position. 3.An assembly as claimed in claim 2, wherein there is provided a baseplate (27), and an inner cross member (26), said inner cross memberconnecting said base plate (27) to said support member (18) in a spacedrelationship thereto, at least an inner half of said rotary saw blade(15) being located between said support member (18) and said base plate(27).
 4. An assembly as claimed in claim 2, including a yolk (28), saidyolk projecting from a lower edge of said lower part (11) of saidcarrier (5), said yolk further projecting below said rotary saw blade(15) to protect said rotary saw blade (15) and associated componentsfrom contact with external material when said rotary saw blade (15) isin an inactive position.
 5. An assembly as claimed in claim 1, whereinsaid cutting tool (12) comprises a chain saw.
 6. An assembly as claimedin claim 2, wherein said support member is a plate.
 7. An assembly asclaimed in claim 1, wherein said cutting tool includes a chain-saw guidebar.